An inkjet printer includes inkjet heads, each having a nozzle surface. The nozzle surfaces of the inkjet heads are covered or sealed with corresponding head caps. One suctioning pump is sequentially connected to the head caps to suction ink from nozzles of the inkjet heads. Viscous ink in internal passages of the inkjet heads, including the nozzles, is discharged into the head caps. Thus, ink ejection performance of the inkjet heads is improved.